From fb4b206709a7add798d07d8f2526052f153931ba Mon Sep 17 00:00:00 2001
From: Simon McVittie <smcv@debian.org>
Date: Tue, 12 Jun 2018 10:53:27 +0100
Subject: [PATCH] Allow pkg-config binary to be overridden with PKG_CONFIG

This is one of the de facto standard interfaces used in Linux
distributions for cross-compilation (alongside overriding CC and
similar variables), and in particular is used in Debian and its
derivatives.

Signed-off-by: Simon McVittie <smcv@debian.org>
---
 Makefile | 45 ++++++++++++++++++++++++---------------------
 1 file changed, 24 insertions(+), 21 deletions(-)

diff --git a/Makefile b/Makefile
index f62ba654..97f21639 100644
--- a/Makefile
+++ b/Makefile
@@ -282,15 +282,18 @@ bin_path=$(shell which $(1) 2> /dev/null)
 # The autoupdater uses curl, so figure out its flags no matter what.
 # We won't need this if we only build the server
 
-# set PKG_CONFIG_PATH to influence this, e.g.
-# PKG_CONFIG_PATH=/opt/cross/i386-mingw32msvc/lib/pkgconfig
-ifneq ($(call bin_path, pkg-config),)
-  CURL_CFLAGS ?= $(shell pkg-config --silence-errors --cflags libcurl)
-  CURL_LIBS ?= $(shell pkg-config --silence-errors --libs libcurl)
-  OPENAL_CFLAGS ?= $(shell pkg-config --silence-errors --cflags openal)
-  OPENAL_LIBS ?= $(shell pkg-config --silence-errors --libs openal)
-  SDL_CFLAGS ?= $(shell pkg-config --silence-errors --cflags sdl2|sed 's/-Dmain=SDL_main//')
-  SDL_LIBS ?= $(shell pkg-config --silence-errors --libs sdl2)
+# set PKG_CONFIG_PATH or PKG_CONFIG to influence this, e.g.
+# PKG_CONFIG_PATH=/opt/cross/i386-mingw32msvc/lib/pkgconfig or
+# PKG_CONFIG=arm-linux-gnueabihf-pkg-config
+PKG_CONFIG ?= pkg-config
+
+ifneq ($(call bin_path, $(PKG_CONFIG)),)
+  CURL_CFLAGS ?= $(shell $(PKG_CONFIG) --silence-errors --cflags libcurl)
+  CURL_LIBS ?= $(shell $(PKG_CONFIG) --silence-errors --libs libcurl)
+  OPENAL_CFLAGS ?= $(shell $(PKG_CONFIG) --silence-errors --cflags openal)
+  OPENAL_LIBS ?= $(shell $(PKG_CONFIG) --silence-errors --libs openal)
+  SDL_CFLAGS ?= $(shell $(PKG_CONFIG) --silence-errors --cflags sdl2|sed 's/-Dmain=SDL_main//')
+  SDL_LIBS ?= $(shell $(PKG_CONFIG) --silence-errors --libs sdl2)
 else
   # assume they're in the system default paths (no -I or -L needed)
   CURL_LIBS ?= -lcurl
@@ -1061,8 +1064,8 @@ ifeq ($(NEED_OPUS),1)
       -I$(OPUSDIR)/include -I$(OPUSDIR)/celt -I$(OPUSDIR)/silk \
       -I$(OPUSDIR)/silk/float -I$(OPUSFILEDIR)/include
   else
-    OPUS_CFLAGS ?= $(shell pkg-config --silence-errors --cflags opusfile opus || true)
-    OPUS_LIBS ?= $(shell pkg-config --silence-errors --libs opusfile opus || echo -lopusfile -lopus)
+    OPUS_CFLAGS ?= $(shell $(PKG_CONFIG) --silence-errors --cflags opusfile opus || true)
+    OPUS_LIBS ?= $(shell $(PKG_CONFIG) --silence-errors --libs opusfile opus || echo -lopusfile -lopus)
   endif
   CLIENT_CFLAGS += $(OPUS_CFLAGS)
   CLIENT_LIBS += $(OPUS_LIBS)
@@ -1074,8 +1077,8 @@ ifeq ($(USE_CODEC_VORBIS),1)
   ifeq ($(USE_INTERNAL_VORBIS),1)
     CLIENT_CFLAGS += -I$(VORBISDIR)/include -I$(VORBISDIR)/lib
   else
-    VORBIS_CFLAGS ?= $(shell pkg-config --silence-errors --cflags vorbisfile vorbis || true)
-    VORBIS_LIBS ?= $(shell pkg-config --silence-errors --libs vorbisfile vorbis || echo -lvorbisfile -lvorbis)
+    VORBIS_CFLAGS ?= $(shell $(PKG_CONFIG) --silence-errors --cflags vorbisfile vorbis || true)
+    VORBIS_LIBS ?= $(shell $(PKG_CONFIG) --silence-errors --libs vorbisfile vorbis || echo -lvorbisfile -lvorbis)
   endif
   CLIENT_CFLAGS += $(VORBIS_CFLAGS)
   CLIENT_LIBS += $(VORBIS_LIBS)
@@ -1086,8 +1089,8 @@ ifeq ($(NEED_OGG),1)
   ifeq ($(USE_INTERNAL_OGG),1)
     OGG_CFLAGS = -I$(OGGDIR)/include
   else
-    OGG_CFLAGS ?= $(shell pkg-config --silence-errors --cflags ogg || true)
-    OGG_LIBS ?= $(shell pkg-config --silence-errors --libs ogg || echo -logg)
+    OGG_CFLAGS ?= $(shell $(PKG_CONFIG) --silence-errors --cflags ogg || true)
+    OGG_LIBS ?= $(shell $(PKG_CONFIG) --silence-errors --libs ogg || echo -logg)
   endif
   CLIENT_CFLAGS += $(OGG_CFLAGS)
   CLIENT_LIBS += $(OGG_LIBS)
@@ -1104,8 +1107,8 @@ endif
 ifeq ($(USE_INTERNAL_ZLIB),1)
   ZLIB_CFLAGS = -DNO_GZIP -I$(ZDIR)
 else
-  ZLIB_CFLAGS ?= $(shell pkg-config --silence-errors --cflags zlib || true)
-  ZLIB_LIBS ?= $(shell pkg-config --silence-errors --libs zlib || echo -lz)
+  ZLIB_CFLAGS ?= $(shell $(PKG_CONFIG) --silence-errors --cflags zlib || true)
+  ZLIB_LIBS ?= $(shell $(PKG_CONFIG) --silence-errors --libs zlib || echo -lz)
 endif
 BASE_CFLAGS += $(ZLIB_CFLAGS)
 LIBS += $(ZLIB_LIBS)
@@ -1116,15 +1119,15 @@ ifeq ($(USE_INTERNAL_JPEG),1)
 else
   # IJG libjpeg doesn't have pkg-config, but libjpeg-turbo uses libjpeg.pc;
   # we fall back to hard-coded answers if libjpeg.pc is unavailable
-  JPEG_CFLAGS ?= $(shell pkg-config --silence-errors --cflags libjpeg || true)
-  JPEG_LIBS ?= $(shell pkg-config --silence-errors --libs libjpeg || echo -ljpeg)
+  JPEG_CFLAGS ?= $(shell $(PKG_CONFIG) --silence-errors --cflags libjpeg || true)
+  JPEG_LIBS ?= $(shell $(PKG_CONFIG) --silence-errors --libs libjpeg || echo -ljpeg)
   BASE_CFLAGS += $(JPEG_CFLAGS)
   RENDERER_LIBS += $(JPEG_LIBS)
 endif
 
 ifeq ($(USE_FREETYPE),1)
-  FREETYPE_CFLAGS ?= $(shell pkg-config --silence-errors --cflags freetype2 || true)
-  FREETYPE_LIBS ?= $(shell pkg-config --silence-errors --libs freetype2 || echo -lfreetype)
+  FREETYPE_CFLAGS ?= $(shell $(PKG_CONFIG) --silence-errors --cflags freetype2 || true)
+  FREETYPE_LIBS ?= $(shell $(PKG_CONFIG) --silence-errors --libs freetype2 || echo -lfreetype)
 
   BASE_CFLAGS += -DBUILD_FREETYPE $(FREETYPE_CFLAGS)
   RENDERER_LIBS += $(FREETYPE_LIBS)